Some known wiring substrates provide electrical connections to electrical elements disposed in a particular pattern at an outer surface of the wiring substrate. An example of such a wiring substrate is a probe head, which can have electrically conductive probes disposed in a particular pattern on an outer surface of the probe head and internal wiring to the probes. Embodiments of the invention include a process of adding customization layers to a standard base wiring substrate that provide customized electrical connections to custom placed electrical elements such as probes at an outer surface of the customization layers. Such a process can allow a base wiring substrate with contacts that are not disposed in a desired pattern to be customized to have electrical elements such as probes disposed in a desired pattern that is different than the pattern of the contacts on the base wiring substrate.